Hello,I recently found out that many newer smartphones support lossless audio formats like FLAC, ALAC and such. So now I'm kind of confused which ones bring real high-quality sound and which ones are just deceit.

Such phones will decode FLAC properly, just as well as any computer. What you want is RMAA-type measurements of the devices' audio performance, regardless of the codec used (doesn't matter if you play FLACs, WAVs or even transparent MP3s). Here's the Galaxy Nexus compared to the iPod Classic and FiiO E7 for instance. The GN loses to the others, but from listening to it a lot, I'd say it sounds decent enough for casual listening on the go without the added bulk of a dedicated device. Other popular smartphones have good reputation regarding sound quality, though I don't have objective evidence handy for any of them.

Using FLAC on a storage limited smartphone would be rather pointless though, IMO. Transparent lossy audio is all you need for listening purposes when storage is an issue.

Hello,I recently found out that many newer smartphones support lossless audio formats like FLAC, ALAC and such. So now I'm kind of confused which ones bring real high-quality sound and which ones are just deceit.